Energizing or tensioning device for spiral springs.



A. I. DAWSON & G. T. BUCKHAM. ENERGIZING 0B TENSIONING DEVICE FOR SPIRAL SPRINGS. APPLICATION FILED APR. I4. I915.

1,292,267, Patented Jan. 21, 1919.

UNITED smarts PATENT orrron.

ARTHUR TREVOR DAWSON AND GEORGE THOMAS BUCKHAM, OF WESTMINSTER, LONDON, ENGLAND, ASSIGNOES TO VICKER'S LIMITED, OF WESTMINSTER,

LONDON, ENGLAND.

ENERGIZING OR TENSIONING- DEVICE FOR SPIRAL SPRINGS.

Specification of Letters Patent.

Patented Jan. 21, 1919.

Application filed April 14, 1915. Serial No. 21,422.

To all whom it may concern:

Be it known that We, Sir ARTHUR TREVOR DAWSON, knight, and GEORGE THOMAS BUoK- HAM, both subjects of the King of Great Britain, residing at Vickers House, Broadway, Westminster, in the county of London, England, have invented certain new and useful Improvements in Energizing or Tensioning Devices for Spiral Springs, of which the following is a specification.

This invention relates to an improved method of and means for adjusting the tension of spiral springs of the kind that are used in connection with the crank shafts of automatic guns, this adjustment of the tension being herein referred to as the energizing or tensioning of the springs. These springs are usually mounted in spring cases composed of two parts, one fixed to the adj acent recoil plate and the other connected to, and therefore movable angularly with, the crank shaft, one end of the spring being connected to the fixed part and the other to the angularly movable part of the spring case. Such arrangements as at present employed are disadvantageous owing to the fact that the energizing 0r tensioning of the spring necessitates two men being employed and leads to a considerable expenditure of time. The chief object of the present invention is to provide an arrangement or device whereby the energizing or tensioning of the spring can be quickly and satisfactorily effected by one person.

According to this invention the spring is energized or tensioned by temporarily connecting the two parts of the case together after a certain amount of tension has been placed on the spring by the rotation of the movable part of the spring case, then disengaging the fixed part of the case from the recoil plate and angularly moving the two parts together with the crank in the proper direction and finally causing the fixed part to rengage with the recoil plate in a different relative angular position. By repeating this operation the requisite number of times the sprin can be tensioned to the desired extent. or the purpose of the invention the aforesaid angularly movable part of the spring case may be slidably connected by a number of keys or otherwise to the crank shaft, and the fixed part may be similarly connected to the recoil plate, the length of the keys appertaining to the fixed part being smaller than that of the keys appertaining to the angularly movable part so that by sliding the two parts outwardly the fixed part can be disengaged from the recoil plate without disengaging the angularly movable part from the crank shaft.

In order that the said invention may be clearly understood and readily carried into effect, we will describe the same more fully with reference to the accompanying drawings, in which Figures 1 and 2 are respectively a sectional one constructional form of the invention as applied to an automatic gun.

Figs. 3 aud t are views similar to Figs. 1 and 2 showing another constructional form of the invention also as applied to an automatic gun.

In these figures, A is the crank shaft and B is part of the recoil plate which is fixed so far as angular movement is concerned. C

is the spiral spring. D is the angularly movable part of the spring casing and E is the fixed part of this casing.

In the example shown by Figs. 1 and 2 the outer end of the crank shaft is provided with three keys a,a, a, set at an angle of 120 degrees apart around the periphery of the crank. These keys engage with corresponding keyways in a hub or sleeve A which has a hexagonal outer surface to receive the angularly movable part D of the spring case which is prevented from moving axially for example by a grub-screw or a screw-threaded stud 03 passing through the boss D of the part D and engaging with the hub or sleeve A. One end of the spiral spring C is attached to the hub or sleeve A and the other end is attached to the part E of the sprin case; this part is connected to a fixed oss B on the recoil plate B by keys and keyways b, b, I), also arranged at an angle of 120 degrees apart, the length of these keys being,.as aforesaid, less than that of the keys a, a, a.

To energize or tension the spring, the crank shaft A is rotated in the direction of the arrow in Fig. 2 against the resistance of the spring C to move the lock to the breech open position, and through an angle sufficient to bring holes d, 01, d in the angularly movable part D of the spring case opposite rear elevation and a side elevation showing corresponding holes 6, e, e in the other part E of the spring case (say 120 degrees). This rotation is effected by means of the crank handle which is not-shown 'butis situated at the end of the crank shaft farthest from the 7 spring case as is well understood; A tommy bar is then inserted into the aforesaid coin-V ciding holes, thus preventing relative angular movement between the two parts D, E from taking; place. The aforesaid grub screw d is then removed and the two parts v ofl the spring case shifted axially outward ;untilzthe keys I), b, :b appertaining to to the fixed {part ;E are clear of their :,keyways, the

keys-a, a, aineanwhile remaining in engage- :ment with their key-ways. The zcrank shaft is then rotated through ana-ng'le -.of 120 degrees in the reverse direction to that indi- I cated;above'. The parts of the spring ease are then pushed back into place to cause the keys *b, b, byto rengagewvithrtheir corre -sponding ,keyways and the" ,tommy bar is withdrawn. The crank shaft and the {part PDIaI'QE-hGIl' intheir original positionrbut the ;point :of attachment-of the springC to the 1 ;part has assumed the newxposition indicated at X in Fig. "2. The {tension on the spring has thus been increased :permanently by itheamount of tension imparted thereto by the; aforesaid movement 'of the part .D in the direction of the arrow. The abov'eldescribed operation is repeated if necessary 'nn'til tthespring has received zthezrequired 1-5andA the-crankshaft A is directly attached degree oftension.

1n the construction illustrated by Fags. 3

to the boss D ofzthe angularly movable part 2D of-the spring case by'rmeans of three keys a, (4,0, arrangedas aforesaid :at an angle 40f E1QO-"degrees apart,zand thiswpartrof the spring scase is prevented from sliding ofl the :keys

by 15a spring pin: or split pin d passing through the boss D and the crank pshaftA, illheifixed .part E of the :spring case is at- :tach'ed to the boss 1B of the adjacent recoil plate :13 :by two setsof keys 6,11, 6 and 'b,

"b,rb-each set being :threeinnumber. These keys are .2 arranged .in :two rows on the boss sat a suitab-ledistanceapart axially and areso placed as :regards their angular positionz'that each A key. of onessetlies opposite a gap r existing between two keys of :the .other set. .Cor-

: ri'espondingczkeywvays are provided in the -fixed part E 0f tthesprin'g case. 7 vThis arirangementjof "keys and Ekeyways thus ,constitu'tes a speciesofbayonetjoint connection .rand zprevents the spring :case from being ac- 'cidentally fully withdrawn from zthe crank iShfiibiWll'GIl-Sflld case :is displaced axially to ifB'edille'ifiXQd part iEsof the case ifrom ithe ja'adj-acent recoil iplate B, owing to the :fact f g/ -lcngthrofithe :keys 6, Z), b and 6, 7)

I {p -tion Inf this 1 construction is :substantially the l lsilejss than that of the keysia. "The'o'per'a- =-semela that ;he einbefore described It is to be understood that our in'iprovements can be employed in conjunction with spiral springs operating-upon oscillatingshafts other than the crank shafts of automatic What we claim and desire to secure by Letters Patent oftheUnited States is 1. A method 10f energizing or tensioning aspiral spring which is connected at one end to a .member normally attached to a fixed part and at the other end to a member attached to an oscillating-shaft, consisting in angularlydisplacing said shaft to place ;a certain amount of tension -on thespring, connecting the two members together, disengaging the first mentioned member from the fixed part to which it is normally attached, angularly moving the two members, :together with theshaft, in the reverse direction to the initial movement-given to the shaft and finally re-connecting said first *.-m entioned *member to its Ffixedgpart in a i different relative angular position.

2. A method ofenerg'izing :or tensioning' .a machine .gun spiral spring which is. connected at one end to a -member normally attached to the recoil plate of the gun and atits'other -;enjd to a member attached -to the oscillatin crank shaft of the g consisting f in. angularly displacing "said crank shaft to place a certain amo nt 'Df tension on the spring, connecting the two 'mem'bers together, disengaging the first mentioned member from the recoilplate to which it is normally attached, angularly moving theitwo membera together with the crank shaft, in the reverse direction to the initial movement given to the crank shaft and finally re:.c0nnectin ,said first .men-

tioned member :to'the'recoil plate in a different angular positlon.

3. In-anapparatusifor energizing 0r tensioning a spiral spring, the combination with an oscillating shaft, a member connected to one end of the spring, ;-'and a second inem ber to which the other end-of the spring is connected, of means for slidably ondymember to whichthe other end-of the spring is .xeonnectedpof means for-'slidably connecting the first mentioned member :to

,saidshafnsa fixed part,:and a key and keyuvayconnection-between said second member: 7

and said fixed part. r r I r 15. In n :apparatus for energizing or ten sioning fa spiral spring, the combination nected to one end of the spring, and a second member to which the other end of the spring is connected, of a key and keyway connection between the first mentioned member and the shaft, and a key and keyway connection between said second member and Said fixed part.

(3. In an apparatus for energizin or tensioning a spiral spring, the conifioination with an oscillating shaft, a member connected to one end of the spring, and a sec- 0nd member to which the other end of the spring is connected, of a sleeve, means for connecting the first mentioned member to the sleeve, means for slidab-ly connecting said sleeve to the shaft, a fixed part and a key and keyway connection between said second member and said fixed part.

7 In an apparatus for energizing or tensioning a spiral spring, the combination with an oscillating shaft, a member connected to one end of the spring, and a sec- 0nd member to which the other end of the spring is connected, of a, key and keywa-y connection between the first mentioned member and the shaft and staggered keys for connecting said second member to said fixed part.

In testimony whereof we affix our signatures in presence of two witnesses.

' ARTHUR TREVOR DAWSGN.

GEORGE THOMAS BUCKHAM.

Witnesses:

HENRY KING, JNo. R. OASWELL.

Copies of this patent may be obtained. for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

